U.S. patent application number 10/578513 was filed with the patent office on 2007-04-12 for method for controlling the longitudinal movement of a motor vehicle.
This patent application is currently assigned to DaimlerChrysler AG. Invention is credited to Bernd Danner, Ingo Dudeck, Helmut Eisele, Wolfgang Lauer, Uwe Regensburger.
Application Number | 20070083309 10/578513 |
Document ID | / |
Family ID | 34559704 |
Filed Date | 2007-04-12 |
United States Patent
Application |
20070083309 |
Kind Code |
A1 |
Danner; Bernd ; et
al. |
April 12, 2007 |
Method for controlling the longitudinal movement of a motor
vehicle
Abstract
In a method for controlling the longitudinal movement of a
vehicle (3), in particular by means of a longitudinal movement
control system, wherein, for vehicle speeds above a threshold
speed, the vehicle speed is adjusted to a higher selected set speed
if no vehicle (8) traveling in front is detected, and if a vehicle
(8) traveling in front is detected the distance from this vehicle
(8) traveling in front is adjusted, below the threshold speed the
longitudinal movement of the vehicle (3) is controlled only if a
vehicle (8) traveling in front is detected. As a result, an
inter-vehicle distance control system can be implemented over a
relatively large speed range.
Inventors: |
Danner; Bernd;
(Achalmstrasse, DE) ; Dudeck; Ingo;
(SchieBackerweg, DE) ; Eisele; Helmut;
(Brombergstrasse, DE) ; Lauer; Wolfgang;
(Solothurner Strasse, DE) ; Regensburger; Uwe;
(Ostfildern, DE) |
Correspondence
Address: |
FITCH, EVEN, TABIN & FLANNERY
P. O. BOX 18415
WASHINGTON
DC
20036
US
|
Assignee: |
DaimlerChrysler AG
Epplestrasse 225
Stuttgart
DE
70567
|
Family ID: |
34559704 |
Appl. No.: |
10/578513 |
Filed: |
September 11, 2004 |
PCT Filed: |
September 11, 2004 |
PCT NO: |
PCT/EP04/12651 |
371 Date: |
August 9, 2006 |
Current U.S.
Class: |
701/41 |
Current CPC
Class: |
B60K 31/0008 20130101;
B60W 30/16 20130101 |
Class at
Publication: |
701/041 |
International
Class: |
B62D 6/00 20060101
B62D006/00 |
Foreign Application Data
Date |
Code |
Application Number |
Nov 19, 2003 |
DE |
103 54 073.3 |
Claims
1. A method for controlling the longitudinal movement of a vehicle
(3), in particular by means of a longitudinal movement control
system, wherein, for vehicle speeds above a threshold speed, the
vehicle speed is adjusted to a higher selected set speed if no
vehicle (8) traveling in front is detected, and if a vehicle (8)
traveling in front is detected the distance from this vehicle (8)
traveling in front is adjusted, characterized in that, below the
threshold speed, the longitudinal movement of the vehicle (3) is
controlled only if a vehicle (8) traveling in front is detected,
the control below the threshold speed being carried out by
adjusting the distance from the vehicle (8) traveling in front.
2. The method as claimed in claim 1, characterized in that a
uniform operating control concept is used for controlling the
longitudinal movement over the entire speed range.
3. The method as claimed in claim 1, characterized in that the
control of the longitudinal movement below the threshold speed is
carried out according to the concept of tracking functionality.
4. The method as claimed in claim 1, characterized in that the
driver of the vehicle is provided with a signal, in particular an
audible and/or visual signal, if the longitudinal movement control
system is not active and/or cannot be activated below the threshold
speed.
5. The method as claimed in claim 1, characterized in that after
the vehicle (3) is in a stationary state, the driver is requested
to enable automatic following of a guide vehicle (8).
6. The method as claimed in claim 1, characterized in that the
maximum deceleration capacity is increased as the vehicle's own
speed drops.
7. The method as claimed in claim 1, characterized in that the
surroundings of the vehicle (3) are sensed in the area in front, in
particular sensed without gaps.
8. The method as claimed in claim 8, characterized in that three
lanes (4-6) are sensed.
9. A longitudinal movement control system of a vehicle (3), in
particular for carrying out the method as claimed in one of the
preceding claims, having a control unit for controlling the
longitudinal movement of the vehicle (3) and having a detection
device for vehicles (8) traveling in front, characterized in that
the system is active and/or can be activated below a threshold
speed only if a vehicle (8) traveling in front is detected, the
control when the system is active below the threshold speed being
carried out by adjusting the distance from the vehicle (8)
traveling in front.
10. The system as claimed in claim 9, characterized in that the
detection device comprises sensors for sensing the short-range area
in front of the vehicle (3) without gaps.
11. The system as claimed in claim 10, characterized in that a
plurality of distributed beam sensors are provided.
Description
[0001] The invention relates to a method for controlling the
longitudinal movement of a vehicle, in particular by means of a
longitudinal movement control system, wherein, for vehicle speeds
above a threshold speed, the vehicle speed is adjusted to a higher
selected set speed if no vehicle traveling in front is detected,
and if a vehicle traveling in front is detected the distance from
this vehicle traveling in front is adjusted.
[0002] Such a method has been disclosed in DE 199 58 520 A1.
[0003] Inter-vehicle distance control systems (adaptive cruise
control (ACC) systems) which are currently offered on the market
operate only in a restricted speed range, for example in the range
from 30 to 180 km/h. In known inter-vehicle distance control
systems a speed is selected and the vehicle is adjusted to this
speed if the distance from a vehicle traveling in front is large
enough or if there is no vehicle traveling in front. If the
distance from the vehicle traveling in front is shorter or if
another vehicle cuts in in front of the vehicle to be controlled
and the distance therefore becomes less than the safety distance,
the inter-vehicle distance control system automatically brakes the
vehicle until the safety distance from the vehicle now traveling in
front is restored. This method of longitudinal movement control is
referred to as free target selection. In this context, the ACC
system decides automatically which detected object is relevant for
the vehicle to be controlled and which objects are not relevant.
This concept provides the driver with a very high level of comfort.
This concept is particularly suitable at high speeds at which brief
lateral movements of the vehicle to be controlled are not expected.
For this reason, the ACC systems have a switch-on threshold of
generally 30 km/h. For lower speeds the driver does not receive any
support from the ACC system. Known ACC systems switch off
automatically if the speed of the vehicle to be controlled drops
below the switch-on threshold. In such a case, the ACC system
audibly requests the driver to take over driving the vehicle.
[0004] For a newly sensed object a relevance for the driver's own
driving function must be clarified. It is necessary to decide
whether the object is of interest to the function of controlling
the vehicle. In this context basically two types of relevant
objects are differentiated: type 1 objects are objects on the
adjacent lane which move at a lateral speed onto the lane of the
vehicle to be controlled and are thus relevant for the vehicle to
be controlled. Type 2 objects are stationary or moving objects in
the area in front of the vehicle to be controlled, which objects
lie on a collision course, depending on the route.
[0005] In the short-range area, there is often too little time
between the detection of a new object and an adapted reaction
(avoidance maneuver, braking) thereto owing to the typically short
distance. It is therefore frequently not possible to decide in a
reliable way whether a newly sensed object is relevant. For this
reason, at present there is, inter alia, no support provided to the
driver in the short-range area at low speeds.
[0006] Furthermore, the currently used beam sensors for sensing the
vehicle traveling in front have only a small angle of aperture at a
large distance. They therefore sense only a very narrow portion of
the surroundings. In particular in the direct short-range area of
the vehicle, it is not sufficient to observe the surroundings which
are relevant to driving the vehicle. It is not possible, for
example, to sense in good time vehicles which are cutting in.
[0007] DE 199 58 520 A1 discloses a speed controller which not only
adjusts the speed of the vehicle starting from a specific minimum
speed (v1) but also adjusts said speeds below a predefined limiting
speed (v2) as far as the stationary state of the vehicle. With this
speed controller it is possible even to adjust the speed range from
the stationary state as far as the second limiting speed (v2) even
at low speeds which occur very frequently in town traffic, by means
of an additional "stop & go device". This stop & go mode is
effective below the second speed (v2) if the driver has not
switched off the system and himself adjusts the distance from the
vehicle traveling in front and his travel speed. If the vehicle is
traveling in the speed range between v1 and v2, in particular if v1
is less than v2, the driver can select between the operating mode
at relatively high speeds and the stop & go mode. However, he
can also leave the decision to the speed controller itself. There
is a sliding transition between the two states, the driver being
able to determine the time of the state change himself since he is
always informed about the current status. In the known speed
controller there is therefore a need for action by the driver.
Whenever interaction occurs with a human being it is not possible
to rule out incorrect control.
[0008] The objective of the present invention is therefore to
improve the driving comfort and the driving safety in vehicles with
automatic speed setting.
[0009] The objective is achieved according to the invention by
means of a method of the type mentioned at the beginning in which,
below the threshold speed, the longitudinal movement of the vehicle
is controlled only if a vehicle traveling in front is detected.
[0010] This method permits the driver to be supported during the
longitudinal adjustment (maintaining distance from the person in
front) even at low speeds, for example in the stop & go mode or
in slow-moving traffic. In this context, the ACC system is expanded
with a functionality but no other operating mode is used. This
means that the ACC system is also active below the threshold speed
on the condition that there is a vehicle traveling in front. The
driver experiences a continuous system without a change of concept
in the entire supported speed range, for example from 0 to 200
km/h. The driver does not need to acknowledge or trigger a
changeover from one operating mode into another operating mode. A
changeover of the operating mode cannot irritate the driver.
Existing systems can be expanded by the method according to the
invention so that there is also no changeover in the operating
control and display functionality or in the warning concept. The
threshold speed can either be predefined by the driver of the
vehicle or set at the works. The threshold speed is also preferably
set to 30 km/h. When the method is activated, a set speed which
corresponds to the threshold speed or is above it is selected by
the driver. The system can be activated above the threshold speed
at any time, while above the threshold speed the longitudinal
movement control is carried out according to the concept of free
target selection. If the vehicle to be controlled has nothing in
front of it, i.e. no vehicle traveling in front, said vehicle also
being referred to as a guide vehicle, the speed of the driver's
vehicle is adjusted to the set speed. When the method is activated,
the vehicle therefore only travels more slowly than the threshold
speed if a vehicle traveling in front travels at a speed below the
threshold speed. At the same time, the longitudinal movement
control below the threshold speed is carried out by adjusting the
distance from the guide vehicle. At a vehicle speed below the
threshold speed, the speed is not adjusted when there is no guide
vehicle.
[0011] Below the threshold speed, the inter-vehicle distance
control system can therefore be activated only if there is a guide
vehicle. The explanation for this is that a large number of objects
may be relevant at low speeds, inter alia also type 2 objects if
there is no vehicle traveling in front. If these objects are also
to be taken into account at low vehicle speeds below the threshold
speed, the adjustment would have to be carried out according to the
concept of free target selection. However, this is only possible at
a vehicle speed above the threshold speed. For this reason, the
invention assumes there is a guide vehicle for the vehicle control
below the threshold speed so that only type 1 vehicles and vehicles
traveling in front can be relevant as new objects when there are
vehicles cutting in. The driver therefore as it were always
experiences the concept of free target selection.
[0012] The control of the longitudinal movement below the threshold
speed is advantageously only carried out according to the concept
of tracking functionality. This means that the automatic
longitudinal control is support only on a reliably tracked vehicle
traveling in front, as an object which is detected as being
relevant. Therefore, only a vehicle which is cutting in between the
vehicle traveling in front and the vehicle to be controlled or a
vehicle traveling in front of a vehicle which is cutting out are
considered for a change of target. The tracked object does not need
to be explicitly confirmed by the driver. The changeover from the
concept of free target selection above the threshold speed to the
concept of the tracking travel above the threshold speed, and vice
versa, takes place automatically without the driver being aware of
it.
[0013] An object detection means may be provided which filters out
from sensor signals those objects which are significant for the
"tracking travel" function. The detection logic comprises filtering
of the data as a function of the travel speed and distance,
verification of the measurement signals by multiple measurement,
plausibility checking of the sensed objects and tracking of
objects, in which detected objects are tracked over a certain
period.
[0014] The driver of the vehicle is advantageously provided with a
signal, in particular an audible and/or visual signal, if the
longitudinal movement control system is not active and/or cannot be
activated below the predefined speed. In this case, the
longitudinal movement control system is switched off. This is
indicated to the driver.
[0015] In one method variant it is possible to provide that after
the vehicle is in a stationary state, the driver is requested to
enable the automatic following of a vehicle traveling in front.
This means that the vehicle does not drive off automatically after
the stationary state. Automatic following of the guide vehicle does
not take place until after acknowledgement (confirmation) by the
driver, for example by pulling a cruise controller lever
(activating memory) or by pressing the accelerator pedal.
Alternatively, it is also conceivable for the driver to drive away
manually and subsequently switch on the system. This means that the
driver only has to switch on the method or the longitudinal
movement control system but does not have to confirm a target.
[0016] A method variant in which the maximum deceleration capacity
is increased as the vehicle's own speed drops is particularly
preferred. This means that in particular if the driver is traveling
at a short distance from the vehicle traveling in front in
slow-moving traffic, rapid deceleration of the vehicle is made
possible if the vehicle traveling in front slows down or stops.
Rear-end collisions can be avoided by this measure. In particular
it is possible to provide for the deceleration capacity to be
changed gradually as a function of the instantaneous speed.
Alternatively, a deceleration capacity of, for example, 4 m/s.sup.2
below the predefined speed and of approximately 2 m/s.sup.2 at
relatively high speeds can be provided with a fluid transition.
[0017] The surroundings of the vehicle are advantageously sensed in
the area in front, in particular sensed without gaps. This measure
permits improved detection of vehicles cutting in, in particular at
low speeds, owing to an additional sensor system for the
short-range area. This measure permits in particular the vehicle to
travel at low speeds and at a short distance.
[0018] In a further development of the method there is provision
for three lanes to be sensed. This measure ensures that the
longitudinal movement control system functions without difficulty
also when traveling in a traffic jam or in slow-moving traffic on
three-lane roads and vehicles cutting in can be sensed both from
the left-hand lane and from the right-hand lane.
[0019] The invention also relates to a longitudinal movement
control system of a vehicle, in particular an inter-vehicle
distance control system, having a control unit for controlling the
longitudinal movement of the vehicle and having a detection device
for vehicles traveling in front, the system being active and/or
being capable of being activated below a threshold value if a
vehicle traveling in front is detected. Above the threshold speed,
when the vehicle is traveling with no one in front, that is to say
when there is no vehicle traveling in front, the speed of the
vehicle is adjusted to a set speed. If there is a vehicle traveling
in front which is slower than the set speed when the longitudinal
movement control system switches on above the threshold speed, the
distance from the vehicle traveling in front is adjusted. When the
driver's vehicle approaches a relatively slow vehicle or when there
is a vehicle cutting in in front of the vehicle to be controlled,
the speed is reduced and the distance from the vehicle traveling in
front is adjusted to a speed-dependent safety distance. If the
vehicle traveling in front slows down to a speed below the
threshold speed, the vehicle to be controlled is also slowed down
because of the safety distance which is to be maintained. If the
vehicle traveling in front turns off and therefore there is no
guide vehicle, the longitudinal movement control system is
deactivated until the vehicle has reached a speed above the
threshold speed or a guide vehicle is detected again by the
detection device and the system can be activated again by the
driver.
[0020] In one embodiment of the invention, the detection device has
sensors for sensing the short-range area in front of the vehicle
without gaps. In order to sense without gaps the surroundings of
the vehicle in the area in front in the direction of travel of the
vehicle it is thus possible to detect not only the objects which
have already been taken into account in ACC systems of the prior
art, but also, at least in the short-range area (for example up to
30 meters), additional objects in the vehicle's lane and the two
adjacent lanes and to describe their movement behavior. The
relevant object for the control of the longitudinal movement is
determined from this, for example by means of fusion of the sensor
data.
[0021] In one preferred embodiment, a plurality of distributed beam
sensors are provided. This permits three lanes to be sensed in the
area in front of the vehicle. In particular it is possible to
provide two 24 GHz radar short-range sensors and a 77 GHz radar
long-range sensor and to mount them in the bumper. An image of the
surroundings of the vehicle can be generated (merged) from the
sensor data and the system can react thereto. High-resolution
sensors with a large angle of aperture can alternatively be used
and embodied, for example, as scanning infrared sensors with a
scanning range of, for example, .gtoreq.40.degree.. Furthermore,
stereo image processing systems can be used.
[0022] Exemplary embodiments of the invention will be explained in
more detail with reference to a drawing, in which:
[0023] FIG. 1 is a schematic illustration of the invention.
[0024] FIG. 1 is a plan view of a three-lane road 2 in the
direction of travel 1. In the area in front of the vehicle 3, for
which a longitudinal movement control system is to be used, a
vehicle 7-9 is located on each lane 4-6. In a speed range above a
predefined threshold speed, the longitudinal movement control
system operates according to the concept of free target selection.
The system adjusts the distance from the vehicle 8 if the distance
becomes less than a safety distance. If there is no guide vehicle
8, the speed of the vehicle 3 is adjusted to a set speed above the
threshold speed. If there is no vehicle 8 traveling in front on the
driver's own lane 5 when the longitudinal movement control system
is activated, the speed is adjusted to the set speed until a
vehicle 8 appears in the capture range of the sensors of the
vehicle 3 or a vehicle changes onto the driver's own lane 3 and is
sensed. Then, an inter-vehicle distance control process takes
place. If there is a vehicle 8 traveling in front when the
longitudinal movement control system is activated above the set
speed, the distance is immediately adjusted. In the concept of free
target selection, type 1 objects, like the object 10 and the
vehicles 7, 9 if they change onto the lane 5, and type 2 objects
(vehicle 8) are taken into account.
[0025] In a speed range below the threshold speed, the longitudinal
movement control system is active only if a vehicle 8 traveling in
front is detected. The longitudinal movement control system then
operates according to the concept of the tracking travel and takes
into account type 1 objects such as the vehicle 10, and vehicles 8
traveling in front of the vehicle on the driver's own lane if the
vehicle 8 cuts out. The vehicle 10 is located in the short-range
area of the vehicle 3 and is sensed on the adjacent lane 6. At
first, the longitudinal movement control system orientates itself
according to the vehicle 8 traveling in front at a short distance.
As soon as the vehicle 10 moves into the lane 5, a different guide
vehicle is available so that orientation is carried out with the
vehicle 10. The longitudinal movement control system observes the
vehicle 10 so that it can react quickly to the vehicle 10 cutting
in and can trigger deceleration of the vehicle 3. The driver does
not notice the change of concept between free target selection and
tracking travel at all since the operating control concept is
configured in a uniform way. If there is no vehicle 8 traveling in
front, the longitudinal movement control system cannot be activated
below the threshold speed.
* * * * *